Sirius felt like he was banging his head against a wall as Regulus seemed to purposefully misunderstand everything he said, taking him at his worst rather than his attempt to try and be at least a little bit reasonable as they talked. "Maybe that's how you see it, but I see all the choices I made that put me there. Same as the choices you made that put you in the position you were in before you came here." Sirius didn't see a difference and he doubted very much that Regulus' taunting was going to change that.
"I did actually." Sirius shrugged, "I loved having friends who were different than me, I loved having an excuse to try new magic, I loved being able to help people I cared about who cared about me beyond my name. And maybe things went to shit in the end, maybe that's just the way life is, but it was a life I chose for myself." And that was what had mattered.
He sighed, "What did you expect me to do? Not tell you about the friends I'd made? I told you because you are my brother, because I wanted you to know. I didn't tell you because I wanted you to think I was finished with you." He didn't know why they were still doing this to one another.
"Let me ask you why you bothered coming here at all today, if you've already decided why and how I did things?" He asked, frustrated and annoyed, but also curious. "You seem to have me all figured out, so why are you here if you've decided that I don't give a shit about you? Surely you could have saved yourself the headache."